Abstract

Hot pancakes with butter running down the sides, freshly baked biscuits and pastries with butter, hot flaky potatoes with melted butter. Yum! It seems like everything tastes better when you add butter. But what is butter and how is it made? In this food science fair project, you will find out, and you will test different conditions for making butter and determine the best method.

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Introduction

Did you know that butter is actually an ancient food? Records show that butter was being manufactured at least 4000 years ago. Originally butter was likely made from sheep or goat's milk. The earliest recipes for the manufacture of butter, which are thought to have come from nomads in the Middle East, call for the use of a vessel made from the skin of a goat. The skin was sewed together tightly, leaving only a small opening to add the milk, which filled the container half full. The vessel was then suspended from wooden poles and swung until the butter formed. In the earliest centuries, butter was made and shipped from India. By at least the 12th century C.E., the Scandinavians made butter and sent it to the rest of Europe. (The cooler climates in northern Europe, like Scandinavia, helped the butter keep longer before spoiling.) For the last century butter has become progressively produced in factories and is now used in many products, including cake batters and pastries, usually to produce a flaky or creamy texture and a delicious, rich flavor.

Butter has long been made by shaking a container of cream. How does this work? The traditional process begins with making cream. When milk is allowed to sit for a while (up to a week), tiny particles of fat from the milk float to the top, forming a visible layer of fat. This fat is called cream. The cream is continually skimmed from the surface of the milk until no more separates from the milk. To
make butter from the cream, the cream is agitated (stirred up) so that the fat particles get shaken out of position and clump together with other fat particles. The clumping first allows tiny air bubbles to be trapped in the cream, forming a light and airy product you might have had, called whipped cream. But if the agitation is continued, the fat particles start to clump so much that the air can no longer be held by the cream, and butter forms. As you can probably see now, butter is basically the milk's fat. By time the butter forms from the cream, the fat particles have clearly separated from the liquid in the cream. This liquid can be removed and made into buttermilk. This entire butter-making process is called churning. Overall, depending on the type of milk used, it can take about 21 pounds of fresh milk to make just 1 pound of butter!

In this cooking and food science project, you will make your own homemade butter and investigate how the temperature of the cream used affects the butter-making process. Some homemade butter is shown in Figure 1 below. When something is heated up, the tiny particles within it move around faster. How do you think a factor like temperature will affect how cream turns into butter? If the fat particles in the cream are moving faster, how will this affect the butter-making process? Grab a jar and some cream and get ready to find out!

Figure A. This is an example of the wind tunnel you can make,

Terms and Concepts

Butter

Fat

Cream

Buttermilk

Churn

Heat

Rancid

Questions

What is fat? What does it have to do with butter?

How can cream be turned into butter?

How does heat affect the movement of particles?

How do different cultures use butter in their cuisines and their traditions?

What kinds of milk do people use to make butter?

Bibliography

The following websites are great for all kinds of information about butter:

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Materials and Equipment

Cups (3)

Liquid measuring cup

Heavy whipping cream (3 cups)

Clean glass jar with lid and a tight seal, 1-qt. A canning jar with a lid, seal, and ring works best.

Table 1. In your lab notebook, create a data table like this one to record your results in.

After the cups of heavy whipping cream have sat out for 5 hours, pour one of the ½ cups of the room-temperature cream into the 1-quart (qt) clean glass jar.

Tightly put the lid on the jar.

Start shaking the jar. At the same time, start the stopwatch or timer. Shake the jar until butter forms. Note: This could take between 5 to 20 minutes.

Initially, you will see and hear the cream slosh around. Keep shaking!

The cream will gradually thicken as the jar is shaken. Eventually, after several seconds (but less than two minutes), the cream will get so thick that it will not move much as you are shaking. At this point the cream has likely turned into whipped cream. Keep shaking the jar, even if you do not hear any sloshing!

Once you have shaken the cream enough (after around 5 to 20 minutes), the liquid (which can be made into buttermilk) will separate from the butter. This change happens very suddenly, over a few seconds. The butter will be a pale yellow color, while the liquid will be thin and milky. At this point the bottom of your jar may look similar to the one in Figure 2 below.

Tip: Previously the cream may have coated the sides of the jar, but at this point a semi-solid lump (which is the butter) will form in the jar and a liquid will probably wash off the jar's sides. You will probably hear the lump hitting the sides of the jar as you shake it.

Stop the stopwatch when the butter and liquid separate.

In the data table in your lab notebook, write down how long it took the butter to form (in minutes) for Trial 1 of the room-temperature cream.

Tip: If it took a certain number of minutes and seconds for the butter to form, convert the seconds into minutes and add this to the minutes. You can convert seconds into minutes by dividing the seconds by 60 (since there are 60 seconds in one minute). For example, if it took 7 minutes and 30 seconds for the butter to form, you would write down 7.5 minutes (since 30 divided by 60 is 0.5). Alternatively, if it took 7 minutes and 20 seconds, you would write down 7.3 minutes (since 20 divided by 60 is 0.3).

Record any other observations about the butter in the data table in your lab notebook.

Figure 2. When the jar of cream is shaken long enough, the butter (the yellow clump) should separate from the milky liquid surrounding it.

Carefully pour the liquid out of the jar.

You can store the liquid in a cool spot and later turn it into buttermilk for use in other recipes. (Tip: You will want to look more into how to do this, but making buttermilk from this liquid is often done by getting some cultured buttermilk from the grocery store, adding a small amount of this to the liquid, and then letting the buttermilk sit on a counter at room temperature for about 12 hours.)

Replace the lid and shake the jar for about another 10 seconds to smooth out the butter and to separate out any more liquid.

Pour out any remaining liquid.

Remove the lump of butter from the jar and place it in a bowl of cold water, as shown in Figure 3 below. Wash your hands and gently knead the butter to remove any extra liquid. Use your fingers to drain the liquid from the bowl.

Figure 3. Place the butter in a bowl of cold water. Remove the liquid by kneading and rinsing the butter.

Repeat step 9 two more times, using the same bowl but with fresh cold water each time.

If all the liquid is not removed, the butter will go rancid faster.

Transfer the butter into a sealable plastic bag. Use a permanent marker to label the plastic bag with the initial conditions of the cream (room temperature or refrigerated).

Clean the jar, its lid, and the bowl.

Repeat steps 3-12, with the room-temperature cream, two more times. You should now have three batches of butter made from room-temperature cream.

When you repeat the process the second time, in step 5e record your data as Trial 2, and when you repeat it the third time, record your data as Trial 3.

Try to shake the jar as similarly as you can between the different trials.

Repeating your results like this helps show that they are accurate and reproducible.

Repeat steps 3-13, but this time in step 3 use ½ cup of cold cream straight from the refrigerator. Do not bring the cream to room temperature.

Your data table should now be all filled in. Now that you have a complete set of data, it is time to analyze it. Using your data, make a bar graph of how long it took the room-temperature cream and the cold cream to turn into butter.

You can make a graph by hand or use a website like Create a Graph to make a graph on the computer and print it.

Make a bar for each trial. Put the trial number and condition name (i.e., "room-temperature cream" or "cold cream") on the x-axis (the horizontal axis going across) and the time until the butter formed (in minutes) on the y-axis (the vertical axis going up and down).

Based on your data, does it look like the temperature affected how quickly the cream turned into butter? Why do you think you got the results that you did? What does this tell you about how butter can be made more quickly from cream?

Hint: For help figuring out why you got the results that you did, try re-reading the Introduction in the Background tab, focusing on how cream turns into butter and the section at the end about heat.

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Variations

Compare the taste of your homemade butter to store-bought butter. Can you see and taste the difference?

Weigh the amount of cream that you start with. Weigh the amount of butter that you end with. What percent of cream turned into butter?

In this food science project you investigated how temperature affects turning cream into butter, but you did not quantify the temperatures you used. You could try this science project again but this time use a thermometer to measure the temperature of the heavy whipping cream when you put it into the glass jar. You could even try some different temperatures and see how they affect the process as well.

You could try culturing the heavy whipping cream with yogurt before you turn the cream into butter. To do this, try adding a few tablespoons of yogurt (that has live and active cultures) to the heavy whipping cream and let it sit out for about 12 hours in a warm room. This should thicken and ferment the cream. (After sitting out, if it smells yeasty or bad, or is bubbly, then do not use it to make butter.) How does butter made from cream cultured with yogurt compare to butter made that is not cultured with yogurt?

Butter is often made at home using a food processor or mixer. Look into how to do this and have an adult help you try it. How does making butter using a machine like this compare to making butter by shaking cream in a glass jar?

Ghee is a product that is made from butter and is also known as clarified butter. Look into how ghee is made and try making ghee from your butter. Explore how making ghee extends the shelf life and extends cooking temperatures.

Ask an Expert

The Ask an Expert Forum is intended to be a place where students can go to find answers to science questions that they have been unable to find using other resources. If you have specific questions about your science fair project or science fair, our team of volunteer scientists can help. Our Experts won't do the work for you, but they will make suggestions, offer guidance, and help you troubleshoot.

Related Links

If you like this project, you might enjoy exploring these related careers:

Food Scientist or Technologist

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Biochemist

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